One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water?video.That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.

One of the most common eye disorders, dry eye disease, causes irritation or discomfort, and can decrease functional vision, sometimes causing a dramatic deterioration in the quality of life. About five million Americans over age 50 suffer from moderate-to-severe dry eyes, and tens of millions more have mild or episodic manifestations of the disease, at a cost of more than $50 billion.

In terms of treatment, there are several drops and drugs that can help. We spend hundreds of millions of dollars on things like artificial tears, but currently there is no therapy available to actually fix the problem. If drugs don't work, doctors can try plugging up the outflow tear ducts, but that can cause complications, such as plugs migrating and eroding into the face, requiring surgical removal. Alternatively, surgeons can just cauterize or stitch up the ducts in the first place.

There has to be a better way.

What about prevention? Dry eyes can be caused by LASIK surgery, affecting about 20-40% of patients six months after the operation. With a million LASIK procedures performed annually, that's a lot of people, and sometimes the long-term symptoms can be severe and disabling.

There's a long list of drugs that can cause it, including antihistamines, decongestants, nearly all the antidepressants, anticonvulsants, antipsychotics, anti-Parkinson's drugs, beta-blockers, and hormone replacement therapy, as well as a few herbal preparations.

In the developing world, vitamin A deficiency can start out as dry eyes and then progress to becoming the leading cause of preventable childhood blindness. Vitamin A deficiency is almost never seen in the developed world, unless you do it intentionally. There was a report in the 1960s of a guy who deliberately ate a vitamin A-deficient diet, living off of bread and lime juice for five years, and his eyes developed vascularization and ulceration of the cornea, which you can see (if you dare) in my Treating Dry Eye Disease with Diet: Just Add Water?video.That was better than what happened to an unfortunate woman who was the member of a cult and tried to live off of brown rice and herbal tea: Her eyes literally melted and collapsed.

There are also a couple case reports of autistic children who refused to eat anything but French fries or menus exclusively comprised of bacon, blueberry muffins, and Kool-Aid, and became vitamin A deficient. A case in the Bronx was written up as vegan diet and vitamin A deficiency, but it had nothing to do with his vegan diet--the kid refused to eat vegetables, consuming only potato chips, puffed rice cereal with non-fortified soymilk, and juice drinks. "His parents lacked particular skill in overcoming the child's tendency to avoid fruits and vegetables."

A plant-based diet may actually be the best thing for patients with dry eye disease, those who wear contact lenses, and those who wish to maximize their tear secretions. People with dry eyes should be advised to lower protein, total fat, and cholesterol intake, and do the following:

We know dehydration can cause a dry mouth, but could dehydration cause dry eyes? It may seem kind of obvious, but evidently it was never studied until recently. Is the answer to just drink more water? We know that those suffering from dry eye are comparatively dehydrated, so researchers figured that tear secretion decreases with progressive dehydration just like saliva secretion decreases and gives us a dry mouth. And indeed, as one gets more and more dehydrated, their urine concentrates and so does the tear fluid. But one can reverse that with rehydration, raising the exciting prospect that improving whole-body hydration by getting people to drink more water might bring relief for those with dry eyes. The researchers recommend eight cups of water a day for women and ten cups a day for men.

Irritable bowel syndrome (IBS) is a chronic, episodic intestinal disorder characterized by abdominal pain and altered bowel habits. It affects 1 in 7 Americans, although most go undiagnosed. IBS can have a substantial impact on well-being and health, but doctors underestimate the impact the disease can have, particularly the pain and discomfort. Using some measures, the health-related quality of life of irritable bowel sufferers can rival that of sufferers of much more serious disorders, such as diabetes, kidney failure, and inflammatory bowel diseases. The first step toward successful treatment is for doctors to acknowledge the condition and not just dismiss the patient as just hysterical or something.

Another reason sufferers often don't seek medical care may be the lack of effectiveness of the available treatments. There is a huge unmet therapeutic need. Since IBS has no cure, treatment is targeted to alleviate the symptoms. Typical antispasmodic drugs can cause side effects, including dry mouth, dizziness, blurred vision, confusion, and fall risk. New drugs now on the market, like Lubiprostone and Linaclotide, can cost up to $3,000 a year and can cause as side effects many of symptoms we're trying to treat.

Antidepressants are commonly given but may take weeks or even months to start helping. Prozac or Celexa take 4 to 6 weeks to help, and Paxil can take up to 12 weeks. They also have their own array of side effects, including sexual dysfunction in over 70% of the people who take these drugs.

There's got to be a better way.

Acupuncture works, but not better than placebo. Placebo acupuncture? That's where you poke people with a fake needle away from any known acupuncture points. Yet that worked just as well as real acupuncture, showing the power of the placebo effect.

I've talked about the ethics of so many doctors who effectively pass off sugar pills as effective drugs, arguing that the ends justify their means. There's actually a way to harness the placebo effect without lying to patients, though. We tell them it's a sugar pill. Patients with irritable bowel syndrome were randomized to either get nothing or a prescription medicine bottle of placebo pills with a label clearly marked "placebo pills" "take 2 pills twice daily." I kid you not.

Lo and behold, it worked! That's how powerful the placebo effect can be for irritable bowel. They conclude that for some disorders it may be appropriate for clinicians to recommend that patients try an inexpensive and safe placebo. Indeed, sugar pills probably won't cost $3,000 a year. But is there a safe alternative that actually works?

As you can see in my video, Peppermint Oil for Irritable Bowel Syndrome, nine randomized placebo-controlled studies have indeed found peppermint oil to be a safe and effective treatment for irritable bowel syndrome. A few adverse events were reported, but were mild and transient in nature, such as a peppermint taste, peppermint smell, and a cooling sensation around one's bottom on the way out. In contrast, in some of the head-to-head peppermint versus drug studies, some of the drug side effects were so unbearable that patients had to drop out of the study. This suggests it might be a reasonable approach for clinicians to treat IBS patients with peppermint oil as a first-line therapy, before trying anything else.

The longest trial only lasted 12 weeks, so we don't yet know about long-term efficacy. The benefits may last at least a month after stopping, though, perhaps due to lasting changes in our gut flora.

The studies used peppermint oil capsules so researchers could match them with placebo pills. What about peppermint tea? It's never been tested, but one might assume it wouldn't be concentrated enough. However, a quarter cup of fresh peppermint leaves has as much peppermint oil as some of the capsule doses used in the studies. One could easily blend it into a smoothie or with frozen berries to make something like my pink juice recipe. You can grow mint right on your window sill.

We doctors need effective treatments that "are cheap, safe, and readily available. This is particularly relevant at the present time as newer and more expensive drugs have either failed to show efficacy or been withdrawn from the market owing to concerns about serious adverse events." Just like it may be a good idea to only eat foods with ingredients you can pronounce, it may be better to try some mint before novel pharmacological approaches, such the new dual mu-opioid agonist delta-antagonist drug with a name like JNJ-27018966.

Irritable bowel syndrome (IBS) is a chronic, episodic intestinal disorder characterized by abdominal pain and altered bowel habits. It affects 1 in 7 Americans, although most go undiagnosed. IBS can have a substantial impact on well-being and health, but doctors underestimate the impact the disease can have, particularly the pain and discomfort. Using some measures, the health-related quality of life of irritable bowel sufferers can rival that of sufferers of much more serious disorders, such as diabetes, kidney failure, and inflammatory bowel diseases. The first step toward successful treatment is for doctors to acknowledge the condition and not just dismiss the patient as just hysterical or something.

Another reason sufferers often don't seek medical care may be the lack of effectiveness of the available treatments. There is a huge unmet therapeutic need. Since IBS has no cure, treatment is targeted to alleviate the symptoms. Typical antispasmodic drugs can cause side effects, including dry mouth, dizziness, blurred vision, confusion, and fall risk. New drugs now on the market, like Lubiprostone and Linaclotide, can cost up to $3,000 a year and can cause as side effects many of symptoms we're trying to treat.

Antidepressants are commonly given but may take weeks or even months to start helping. Prozac or Celexa take 4 to 6 weeks to help, and Paxil can take up to 12 weeks. They also have their own array of side effects, including sexual dysfunction in over 70% of the people who take these drugs.

There's got to be a better way.

Acupuncture works, but not better than placebo. Placebo acupuncture? That's where you poke people with a fake needle away from any known acupuncture points. Yet that worked just as well as real acupuncture, showing the power of the placebo effect.

I've talked about the ethics of so many doctors who effectively pass off sugar pills as effective drugs, arguing that the ends justify their means. There's actually a way to harness the placebo effect without lying to patients, though. We tell them it's a sugar pill. Patients with irritable bowel syndrome were randomized to either get nothing or a prescription medicine bottle of placebo pills with a label clearly marked "placebo pills" "take 2 pills twice daily." I kid you not.

Lo and behold, it worked! That's how powerful the placebo effect can be for irritable bowel. They conclude that for some disorders it may be appropriate for clinicians to recommend that patients try an inexpensive and safe placebo. Indeed, sugar pills probably won't cost $3,000 a year. But is there a safe alternative that actually works?

As you can see in my video, Peppermint Oil for Irritable Bowel Syndrome, nine randomized placebo-controlled studies have indeed found peppermint oil to be a safe and effective treatment for irritable bowel syndrome. A few adverse events were reported, but were mild and transient in nature, such as a peppermint taste, peppermint smell, and a cooling sensation around one's bottom on the way out. In contrast, in some of the head-to-head peppermint versus drug studies, some of the drug side effects were so unbearable that patients had to drop out of the study. This suggests it might be a reasonable approach for clinicians to treat IBS patients with peppermint oil as a first-line therapy, before trying anything else.

The longest trial only lasted 12 weeks, so we don't yet know about long-term efficacy. The benefits may last at least a month after stopping, though, perhaps due to lasting changes in our gut flora.

The studies used peppermint oil capsules so researchers could match them with placebo pills. What about peppermint tea? It's never been tested, but one might assume it wouldn't be concentrated enough. However, a quarter cup of fresh peppermint leaves has as much peppermint oil as some of the capsule doses used in the studies. One could easily blend it into a smoothie or with frozen berries to make something like my pink juice recipe. You can grow mint right on your window sill.

We doctors need effective treatments that "are cheap, safe, and readily available. This is particularly relevant at the present time as newer and more expensive drugs have either failed to show efficacy or been withdrawn from the market owing to concerns about serious adverse events." Just like it may be a good idea to only eat foods with ingredients you can pronounce, it may be better to try some mint before novel pharmacological approaches, such the new dual mu-opioid agonist delta-antagonist drug with a name like JNJ-27018966.

Irritable bowel syndrome (IBS) is a chronic, episodic intestinal disorder characterized by abdominal pain and altered bowel habits. It affects 1 in 7 Americans, although most go undiagnosed. IBS can have a substantial impact on well-being and health, but doctors underestimate the impact the disease can have, particularly the pain and discomfort. Using some measures, the health-related quality of life of irritable bowel sufferers can rival that of sufferers of much more serious disorders, such as diabetes, kidney failure, and inflammatory bowel diseases. The first step toward successful treatment is for doctors to acknowledge the condition and not just dismiss the patient as just hysterical or something.

Another reason sufferers often don't seek medical care may be the lack of effectiveness of the available treatments. There is a huge unmet therapeutic need. Since IBS has no cure, treatment is targeted to alleviate the symptoms. Typical antispasmodic drugs can cause side effects, including dry mouth, dizziness, blurred vision, confusion, and fall risk. New drugs now on the market, like Lubiprostone and Linaclotide, can cost up to $3,000 a year and can cause as side effects many of symptoms we're trying to treat.

Antidepressants are commonly given but may take weeks or even months to start helping. Prozac or Celexa take 4 to 6 weeks to help, and Paxil can take up to 12 weeks. They also have their own array of side effects, including sexual dysfunction in over 70% of the people who take these drugs.

There's got to be a better way.

Acupuncture works, but not better than placebo. Placebo acupuncture? That's where you poke people with a fake needle away from any known acupuncture points. Yet that worked just as well as real acupuncture, showing the power of the placebo effect.

I've talked about the ethics of so many doctors who effectively pass off sugar pills as effective drugs, arguing that the ends justify their means. There's actually a way to harness the placebo effect without lying to patients, though. We tell them it's a sugar pill. Patients with irritable bowel syndrome were randomized to either get nothing or a prescription medicine bottle of placebo pills with a label clearly marked "placebo pills" "take 2 pills twice daily." I kid you not.

Lo and behold, it worked! That's how powerful the placebo effect can be for irritable bowel. They conclude that for some disorders it may be appropriate for clinicians to recommend that patients try an inexpensive and safe placebo. Indeed, sugar pills probably won't cost $3,000 a year. But is there a safe alternative that actually works?

As you can see in my video, Peppermint Oil for Irritable Bowel Syndrome, nine randomized placebo-controlled studies have indeed found peppermint oil to be a safe and effective treatment for irritable bowel syndrome. A few adverse events were reported, but were mild and transient in nature, such as a peppermint taste, peppermint smell, and a cooling sensation around one's bottom on the way out. In contrast, in some of the head-to-head peppermint versus drug studies, some of the drug side effects were so unbearable that patients had to drop out of the study. This suggests it might be a reasonable approach for clinicians to treat IBS patients with peppermint oil as a first-line therapy, before trying anything else.

The longest trial only lasted 12 weeks, so we don't yet know about long-term efficacy. The benefits may last at least a month after stopping, though, perhaps due to lasting changes in our gut flora.

The studies used peppermint oil capsules so researchers could match them with placebo pills. What about peppermint tea? It's never been tested, but one might assume it wouldn't be concentrated enough. However, a quarter cup of fresh peppermint leaves has as much peppermint oil as some of the capsule doses used in the studies. One could easily blend it into a smoothie or with frozen berries to make something like my pink juice recipe. You can grow mint right on your window sill.

We doctors need effective treatments that "are cheap, safe, and readily available. This is particularly relevant at the present time as newer and more expensive drugs have either failed to show efficacy or been withdrawn from the market owing to concerns about serious adverse events." Just like it may be a good idea to only eat foods with ingredients you can pronounce, it may be better to try some mint before novel pharmacological approaches, such the new dual mu-opioid agonist delta-antagonist drug with a name like JNJ-27018966.

Over the counter antacids are probably the most important source for human aluminum exposure in terms of dose. For example, Maalox, taken as directed, can exceed the daily safety limit more than 100-fold, and nowhere on the label does it say to not take it with acidic beverages such as fruit juice. Washing an antacid down with orange juice can increase aluminum absorption 8-fold, and citric acid-the acid found naturally concentrated in lemon and limes--is even worse.

Just as sour fruits can enhance the absorption of iron (a good thing), the same mechanism they may enhance the absorption of aluminum (a bad thing). This raises the question of what happens when one adds lemon juice to tea? Previously, I concluded that the amount of aluminum in tea is not a problem for most people because it's not very absorbable (See Is There Too Much Aluminum in Tea?). What if we add lemon? Researchers publishing in the journal Food and Chemical Toxicologyfound no difference between tea with lemon, tea without lemon, or no tea at all in terms of the amount of aluminum in the bloodstream, suggesting that tea drinking does not significantly contribute to aluminum getting inside the body.

The researchers used black tea, green tea, white tea, oolong tea, but what about the "red zinger" herbal tea, hibiscus? The reason hibiscus tea is called "sour tea" is because it has natural acids in it like citric acid. Might these acids boost the absorption of any hibiscus's aluminum? While a greater percentage of aluminum gets from the hibiscus into the tea water than from the other teas, there's less aluminum overall.

The real question is whether the aluminum then gets from the tea water into our bodies. We don't have that data, so to be on the safe side we should assume the worst: that hibiscus tea aluminum, unlike green and black tea aluminum, is completely absorbable. In that case, based on this data and the World Health Organization weekly safety limit, we may not want to drink more than 15 cups of hibiscus tea a day, (based on someone who's about 150 pounds). If you have a 75 pound 10-year-old, a half-gallon a day may theoretically be too much. Recent, more extensive testing highlighted in my video, How Much Hibiscus Tea is Too Much?, suggests that levels may reach level twice as high. Therefore, to be safe, no more than about two quarts a day for adults, or one quart a day for kids or pregnant women. Hibiscus tea should be completely avoided by infants under six months--who should only be getting breast milk--as well as kids with kidney failure, who can't efficiently excrete it.

There is also a concern about the impressive manganese level in hibiscus tea. Manganese is an essential trace mineral, a vital component of some of our most important antioxidant enzymes, but we probably only need about two to five milligrams a day. Four cups of hibiscus tea can have as much as 17 milligrams, with an average of about ten. Is that a problem?

One study from the University of Wisconsin found that women given 15 milligrams of manganese a day for four months, saw, if anything, an improvement in their anti-inflammatory, anti-oxidant enzyme activity. Another study using 20 milligrams a day similarly showed no adverse short-term effects, and importantly showed that the retention of dietary manganese is regulated. Our bodies aren't stupid; if we take in too much manganese, we decrease the absorption and increases the excretion. Even though tea drinkers may get ten times the manganese load (10 or 20 milligrams a day) the levels in their blood are essentially identical. There is little evidence that dietary manganese poses a risk.

These studies were conducted with regular tea, though, so we don't know about the absorption from hibiscus. To err on the side of caution we should probably not routinely exceed the reference dose of ten milligrams per day, or about a quart a day for adults and a half-quart for a 75 pound child.

I've actually changed my consumption. Given the benefits of the stuff, I was using it as a substitute for drinking water, drinking around two quarts a day. I was also blending the hibiscus petals in, not throwing them away, effectively doubling the aluminum content, and increasing manganese concentrations by about 30%. So given this data I've cut back to no more than a quart of filtered hibiscus tea a day.

While aluminum is the third most abundant element on Earth, it may not be good for our brain, something we learned studying foundry workers exposed to particularly high levels. Although the role of aluminum in the development of brain diseases like Alzheimer's is controversial, to be prudent, steps should probably be taken to lessen our exposure to this metal.

There are a number of aluminum-containing drugs on the market (like antacids, which have the highest levels), though aluminum compounds are also added to processed foods such as anti-caking agents in pancake mix, melting agents in American cheese, meat binders, gravy thickeners, rising agents in some baking powders and dye-binders in candy. Therefore, it's better to stick to unprocessed, natural foods. Also, if you cook those natural foods in an aluminum pot, a significant amount of aluminum can leach into the food (compared to cooking in stainless steel).

When researchers tried the same experiment with tea, they got a few milligrams of aluminum regardless of what type of pot they used, suggesting that aluminum was in the tea itself. Indeed, back in the 1950's researchers noticed that tea plants tended to suck up aluminum from the soil. But it's the dose that makes the poison. According to the World Health Organization, the provisional tolerable weekly intake--our best guess at a safety limit for aluminum--is two mg per healthy kilogram of body weight per week, which is nearly a milligram per pound. Someone who weighs around 150 pounds probably shouldn't ingest more than around 20 mg of aluminum per day.

Up to a fifth of aluminum intake may come from beverages, so what we drink probably shouldn't contribute more than about four mg a day, the amount found in about five cups of green, black, or oolong tea. So should we not drink more than five cups of tea a day?

It's not what you eat or drink, it's what you absorb. If we just measured how much aluminum was in tea, it would seem as though a couple cups could double aluminum intake for the day. But if we measure the level of aluminum in people's bodies after they drink tea, it doesn't go up. This suggests that the bioavailability of aluminum in tea is low, possibly because most of the extractable aluminum in brewed tea is strongly bound to large phytonutrients that are not easily absorbed, so the aluminum just passes right through us without actually getting into our bodies. Probably more than 90 percent of the aluminum in tea is bound up.

One study out of Singapore, highlighted in my video, Is There Too Much Aluminum in Tea? did show a large spike in aluminum excretion through the urine after drinking tea compared to water. The only way for something to get from our mouth to our bladder is to first be absorbed into our bloodstream. But the researchers weren't comparing the same quantity of tea to water. They had the study subject chug down about eight and a half cups of tea, or drink water at their leisure. Therefore, the tea drinkers peed a lot more, so the aluminum content cup-for-cup was no different for tea versus water. This suggests that gross aluminum absorption from tea is unlikely and that only a little aluminum is potentially available for absorption.

So although as few as four cups of tea could provide 100 percent of our daily aluminum limit, the percentage available for absorption in the intestine may be less than 10 percent. It is therefore unlikely that moderate amounts of tea drinking can have any harmful effects--for people with normal aluminum excretion. Tea may not, however, be a good beverage for children with kidney failure, since they can't get rid of aluminum as efficiently. For most people, though, tea shouldn't be a problem.

On a special note, if you drink tea out of a can, buy undented cans. The aluminum in dented cans can leach into the liquid, boosting aluminum levels by a factor of eight while sitting on store shelves for a year.

Hibiscus tea has been found to be as effective at lowering blood pressure as a leading hypertension drug without the potential side-effects (which include everything from lack of strength to impotence, including rare cases of potentially fatal liver damage). Hibiscus, though, may have adverse effects of its own.

As I've reviewed previously in Plant-Based Diets: Oral Health, people who eat plant-based diets appear to have superior periodontal health, including less gum disease and fewer signs of inflammation, like bleeding. However, they also have twice the prevalence of dental erosions, areas on the teeth where the enamel has thinned due to more frequent consumption of acidic fruits and vegetables. Therefore, after we eat something like citrus, we should swish our mouths with water to clear the acid from our teeth.

This includes beverages. I'm a big fan of hibiscus tea, but it's not called "sour tea" for nothing. In a study highlighted in my video, Protecting Teeth from Hibiscus Tea, researchers at the University of Iowa dental school tested 25 different popular teas and found two with a pH under 3 (as acidic as orange juice or coca cola): Tazo's passion and Bigelow's red raspberry, both of which contain hibiscus as their first ingredient.

To see if these teas could actually dissolve teeth, the researchers took 30 extracted molars from people and soaked them in different teas. And indeed, out of the five teas tested, the greatest erosion came from the tea with the most hibiscus. The researchers left the tooth sitting in the tea for 25 hours straight, but this was to simulate a lifetime of exposure. The bottom line is that herbal teas are potentially erosive, particularly fruity and citrusy teas like hibiscus. To minimize the erosive potential, we can use a straw to drink the beverage. And as I mentioned above, after consuming an acidic food or drink we should also rinse our mouth with water to help neutralize the acid.

Recently, researchers from Taiwan pitted the herbal tea hibiscus against obesity. They gave hibiscus to overweight individuals and reported that subjects showing reduced body weight. However, after 12 weeks on hibiscus subjects only lost about three pounds, only one and a half pounds over placebo. Hibiscus is clearly no magic fix for obesity.

The purported cholesterol-lowering property of hibiscus tea looked a bit more promising. Some older studies suggested as much as an 8% reduction from drinking two cups a day for a month. When all the studies are put together, though, the results are pretty much a wash. This may be because only about 50% of people respond at all to drinking the equivalent of between two to five cups a day, though those that do may get a respectable 12% drop. That's nothing like the 30% one can get within weeks of eating a healthy, plant-based diet, though.

Hibiscus may really shine in treating high blood pressure, a disease affecting a billion people and killing millions. Up until 2010, there wasn't sufficient high quality research to support the use of hibiscus tea to treat hypertension, but there are now randomized double-blind, placebo-controlled studies where hibiscus tea is compared to artificially colored and flavored water that looks and tastes like hibiscus tea, and the tea lowers blood pressure significantly better.

We're still not sure how it works, but hibiscus appears to boost nitric oxide production, which could help our arteries relax and dilate better. Regardless, an updated review acknowledged that the daily consumption of hibiscus tea may indeed significantly lower blood pressures in people with hypertension.

How does hibiscus compare to other blood pressure interventions? The premier clinical trial when it comes to comprehensive lifestyle modification for blood pressure control is the PREMIER Clinical Trial. Realizing that nine out of ten Americans are going to develop hypertension, researchers from John Hopkins randomized 800 men and women with high blood pressure into one of three groups. One was the control group, the so-called "advice only group," where patients were just told to lose weight, cut down on salt, increase exercise and eat healthier. In the two behavioral intervention groups the researchers got serious. Eighteen face-to-face sessions, groups meetings, food diaries, physical activity records, and calorie and sodium intake monitoring. One intervention group just concentrated on exercise; the other included exercise and diet. Researchers pushed the DASH diet, which is high in fruits and vegetables and low in full-fat dairy products and meat. In six months subjects achieved a 4.3 point drop in systolic blood pressure, compared to the control, slightly better than the lifestyle intervention without the diet.

A few points might not sound like a lot--that's like someone going from a blood pressure of 150 over 90 to a blood pressure of 146 over 90--but on a population scale a five point drop in the total number could result in 14% fewer stroke deaths, 9% fewer fatal heart attacks, and 7% fewer deaths every year overall.

A cup of hibiscus tea with each meal didn't just lower blood pressure by three, four, or five points, but by seven points, from an average of 129 down to 122. In fact, tested head-to-head against a leading blood-pressure drug, Captopril, two cups of strong hibiscus tea every morning (five tea bags for the two cups) was as effective in lowering blood pressure as a starting dose of 25mg of captopril taken twice a day.

So hibiscus tea is as good as drugs, without side-effects, and better than diet and exercise? Well, the lifestyle interventions in the PREMIER study were pretty wimpy. As public health experts noted, the PREMIER study was only asking for 30 minutes of exercise a day, whereas the World Health Organization recommends a minimum of an hour a day.

Diet-wise, the lower the animal fat intake, and the more plant sources of protein the PREMIER participants were eating, the better the diet appeared to work. This may explain why vegetarian diets appear to work even better, and the more plant-based, the lower the prevalence of hypertension.

On the DASH diet, subjects cut down on meat, but were still eating it every day, so would qualify as nonvegetarians in the Adventist 2 study (highlighted in my video Hibiscus Tea vs. Plant-Based Diets for Hypertension) which looked at 89,000 Californians. It found that those who only ate meat on a weekly basis had 23% lower rates of high blood pressure. Those who cut out all meat except fish had 38% lower rates. Those eating no meat at all, vegetarians, have less than half the rate. The vegans--cutting out all animal protein and fat--appeared to have thrown three quarters of their risk for this major killer out the window.

One sees the same kind of step-wise drop in diabetes rates as one's diet gets more and more plant-based, and a drop in excess body weight, such that only those eating completely plant-based diets in the Adventist 2 study fell into the ideal weight category. Could that be why those eating plant-based have such great blood pressure? Maybe it's just because they're so skinny. I've previously shown how those eating plant-based just have a fraction of the diabetes risk even at the same weight. but what about hypertension?

The average American has what's called prehypertension, which means the top number of our blood pressure is between 120 and 139. We don't have hypertension yet, which starts at 140, but we may be well on our way. Compare that to the blood pressure of those eating whole food plant-based diets. In one study, those eating plant-based didn't have blood pressures three points lower, four points lower, or even seen points lower, but 28 points lower. However, the group eating the standard American diet was, on average, overweight with a BMI over 26, still better than most Americans, while the vegans were a trim 21--that's 36 pounds lighter.

Maybe the only reason those eating meat, eggs, dairy, and processed junk had such higher blood pressure was because they were overweight. Maybe the diet per se had nothing to do with it?

To solve that riddle we would have to find a group still eating the standard American diet, but as slim as vegans. To find a group that trim, researchers had to use long-distance endurance athletes, who ate the same crappy American diet, but ran an average of 48 miles per week for 21 years. Anyone who runs almost two marathons a week for 20 years can be as slim as a vegan--no matter what they eat!

How did the endurance runners compare to the couch potato vegans? It appears that if we run an average of about a thousand miles every year our blood pressures can rival some couch potato vegans. That doesn't mean we can't do both, but it may be easier to just eat plants.

Those who've been following my work for years have seen how my videos have evolved. In the past, the hibiscus results may have been the whole article or video. But thanks to everyone's support, I've been able to delegate the logistics to staff and concentrate more on the content creation. This allows me to do deeper dives into the literature to put new findings into better context. The posts are a bit longer, but hopefully they're more useful--let me know what you think!

For such a leading killer, hypertension has not gotten the coverage it deserves on NutritionFacts.org. Here's a few videos, with more to come:

We know smoke inhalation isn't good for us, but what about smoke ingestion? Decades ago, smoke flavorings were tested to see if they caused DNA mutations in bacteria--the tests came up negative. Even as more and more smoke flavoring was added, the DNA mutation rate remained about the same.

But the fact that something is not mutagenic in bacteria may have little predictive value for its effect on human cells. A group at MIT tested a hickory smoke flavoring they bought at the store against two types of human white blood cells. Unlike the bacteria, the mutation rate shot up as more and more liquid smoke was added. But, "there is no evidence that mutagenic activity in a particular human cell line is more closely related to human health risk than is mutagenic activity in bacteria." In other words: just because liquid smoke causes DNA mutations to human cells in a petri dish, doesn't mean that it does the same thing within the human body.

A good approach may be to just analyze liquid smoke for known carcinogens, chemicals that we know cause cancer.

Damaging DNA is just one of many ways chemicals can be toxic to cells. A decade later researchers tested to see what effect liquid smoke had on overall cell viability. If you drip water on cells, nothing happens, they keep powering away at around 100% survival, but drip on more and more wood fire smoke, and you start killing some of the cells off. Cigarette smoke is more toxic, but three out of four of the brands of liquid smoke they bought at the supermarket killed off even more cells, leading them to conclude that the cytotoxic potential of some commercial smoke flavorings is greater than that of liquid cigarette smoke, a finding they no doubt celebrated given that the researchers were paid employees of the R. J. Reynolds Tobacco Co.

Unfortunately they didn't name names of the offending brands. That's one of the reasons I was so excited about a new study, where they tested--and named--15 different brands of liquid smoke. This maximum "response" they were measuring was p53 activation.

P53 is a protein we make that binds to our DNA, you can see this illustrated in my video, Is Liquid Smoke Flavoring Carcinogenic?. It activates our DNA repair enzymes. So a big p53 response may be indicative of a lot of DNA damage,and a few of the liquid smoke flavorings activated p53 almost as much as a chemotherapy drug like etoposide, whose whole purpose is to break DNA strands.

Other flavorings didn't seem as bad, though there was a hickory smoke powder that ranked pretty high, as did the fish sauce, though smoked paprika didn't register at all.

The p53-activating property in liquid smoke was eliminated by standard baking conditions (350°F for 1h), so if you're baking something with liquid smoke for long enough, it should eliminate this effect, though just boiling--even for an hour, or slow cooking doesn't appear to work.

They conclude "If the DNA-damaging activities of liquid smoke were thought to be deleterious, it might be possible to replace liquid smoke with other safer, smoky substances." Why do they say if thought to be deleterious? That's because they're not really measuring DNA damage, they're measuring p53 activation, and that's not necessarily a bad thing.

P53 is considered "Guardian of our Genome," guardian of our DNA. It's considered a tumor suppressor gene, so if something boosts its activity is that good or bad? It's like the broccoli story. Cruciferous vegetables dramatically boost our liver's detoxifying enzymes. Is this because our body sees broccoli as toxic and is trying to get rid of it quicker? Either way, the end result is good, lower cancer risk.

It's a biological phenomenon known as hormesis - that which doesn't kill us may make us stronger. Like exercise is a stress on the body, but in the right amount can make us healthier in the long run. So, for example, teas and coffees caused p53 activation as well, but their consumption is associated with lower cancer risk. So it's hard to know what to make of this p53 data. Due to the limitations of the available tests it's hard to calculate the genotoxic potential of liquid smoke, or any other food for that matter. A better approach may be to just analyze liquid smoke for known carcinogens, chemicals that we know cause cancer.

This was first attempted back in 1971. One of the seven liquid smoke flavors researchers tested contained one polycyclic aromatic hydrocarbon known to be cancer-causing, but there's a bunch of similar carcinogens researchers didn't test for. A later study, however, tested across the board, looking specifically at five different carcinogens in retail liquid smoke seasonings.

The recommended daily upper safety limit for these carcinogens is 47. Hickory smoke flavoring has only 0.8 per teaspoon, so we'd have to drink three bottles a day to bump up against the limit. And mesquite liquid smoke has only 1.1.

It turns out that most of the carcinogens in smoke are fat soluble, so when we make a water-based solution, like liquid smoke, we capture the smoke flavor compounds without capturing most of the smoke cancer compounds. The only time we need to really worry is when eating smoked foods--foods directly exposed to actual smoke. For example, smoked ham has 21.3 per serving, and smoked turkey breast has 26.7 per serving. One sandwich and we may be halfway to the limit, and one serving of barbequed chicken takes us over the top. Eating less than a single drumstick and we nearly double our daily allotment of these carcinogens. Nothing, however, is as bad as fish. Smoked herring? 140 per serving. And smoked salmon? One bagel with lox could take us ten times over the limit.